Our free ZIP Analyzer audits internal ZIP file structures, compression ratios, and extension byte density distributions. Inspect central directory records, parse uncompressed vs compressed sizes, and receive optimization recommendations without uploading or extracting files to disk.
Select or drop any ZIP file into the analyzer drop zone.
Our client-side parser reads central directory headers and file records.
Review compression efficiency scores, byte distributions, and optimization tips.
Reads ZIP archive central directory headers instantly to analyze internal structure without extracting file contents.
Compiles interactive charts showing byte consumption percentages grouped by file extensions.
All header parsing runs completely within local JavaScript memory with zero network transfers.
Zip Header Parsing & Metadata Inspection: Analyzing a zip archive without extracting files requires reading binary headers: Local File Headers, Central Directory Records, and End of Central Directory (EOCD) signatures (0x06054b50). BunchTool extracts file counts, uncompressed vs. compressed byte sizes, encryption flags, and individual file compression ratios.
Detecting Malicious Zip Bombs & Corrupted Archives: Analyzing archive structures before extraction protects systems against Zip Bombs (hyper-compressed recursive archives designed to crash servers) and identifies corrupted file blocks using CRC-32 integrity validation.
100% In-Browser Archive Inspection: Archive binary analysis occurs strictly inside client-side browser RAM via WebAssembly threads. Proprietary backups, server logs, and confidential zip files are inspected locally without server network transmission.